Publisher Summary Tin (Sn) compounds are well-recognized both in basic research and in industrial applications. Tin NMR spectroscopy includes three magnetically active tin isotopes namely, 115Sn, 117Sn , and l19Sn. However, most tin NMR parameters refer to the 119Sn nucleus owing to its properties such as abundance, magnetic moment, and NMR frequency. This chapter describes: (1) the compilation and updation of 119Sn chemical shifts (δ 119Sn) from studies on organotin compound and inorganic tin compounds, (2) indirect nuclear spin-spin couplings, (3) relaxation mechanisms concerning the 119Sn nucleus, and (4) experimental details for 1I9Sn-NMR measurements. It is observed that with modem equipment there are, in principle, no serious experimental difficulties in observing 119Sn resonances either directly or by heteronuclear double resonance. δ 119Sn data, available for all kinds of tin compounds, significantly allows using this parameter in an empirical way in order to find models for the qualitative interpretation of δ 119Sn. This also applies to couplings involving the l19Sn nucleus, which serve as a sensitive tool in the discussion of structure and bonding. All 119Sn-NMR parameters of tin compounds largely concern measurements in the liquid state.

119Sn-NMR Parameters

Publisher Summary This chapter describes the measurement of, and factors influencing, 1I9 Sn chemical shifts of organotin compounds. Elemental tin contains 10 naturally occurring isotopes, and only three of these have nonzero nuclear magnetic moments: 115 Sn, 117 Sn, and 119 Sn. Each of the three magnetic tin isotopes has a nuclear spin of 4 and therefore zero quadrupole moment. All three isotopes have approximately equal nuclear magnetic moments. However, in nuclear magnetic resonance (NMR) investigations of tin compounds, the chemical shifts are usually measured for 119 Sn nuclei because of the greater intensity of their NMR signals and because of their higher natural abundance. Fourier transform (FT) NMR spectroscopy, although used extensively to study 13 C and 15 N nuclei, has only very recently been applied to 119 Sn. Pulse FT NMR has been used to study the spin-lattice relaxation times, T 1 , of l19 Sn in a number of organic and inorganic tin compounds. The most important relaxation mechanism for this nucleus in a series of tetraorganotins appears to be spinrotation (SR), although for larger molecules, such as hexabutylditin, dipole–dipole (DD) relaxation is important, even at room temperature.

Chemical Shifts of 119Sn Nuclei in Organotin Compounds

Publisher Summary The literature on organotin chemistry up to 1970 is summarized in the excellent monographs by Neumann and Poller and in the volumes edited by Sawyer. Since that date, periodic reviews of advances in the field, and accounts of some selected aspects have been published, but there has been no attempt to bring the general survey up to date. In this article, one has attempted to review the progress that has been made since 1970, and to give an account of the present status of the field, briefly sketching in the earlier background. About 1000 papers are published annually on organotin chemistry, and only 5% of these have been able to be included. One has deliberately avoided treating in depth those aspects of the subject that have been thoroughly reviewed recently, and in particular, one has avoided duplicating the excellent surveys of the use of organotin compounds in organic synthesis.

Recent Advances in Organotin Chemistry

Als Hohepunkte auf dem Gebiet der Organoelementchemie der schwereren Elemente der vierten Hauptgruppe (Gruppe 14 des Periodensystems) in den 80er Jahren gelten die Darstellung und vollstandige Charakterisierung dreier Verbindungsklassen, deren Existenz bis dahin aufgrund ihrer Reaktivitat fur nicht moglich gehalten wurde. Hierbei handelt es sich um 1) die dreigliedrigen Ringsysteme Cyclotrisilan, -trigerman und -tristannan, 2) Molekule mit Element-Element-Doppelbindungen einschlieslich Disilen, Digermen und Distannen sowie 3) gespannte Polycyclen mit einem Gerust aus den schwereren Elementen der 4. Hauptgruppe, z. B. Bicyclo[1.1.0]tetrasilan, Hexagermaprisman und Octasilacuban. Die meisten dieser Verbindungen sind durch sperrige Substituenten stabilisiert. Die Verbindungen ermoglichten Untersuchungen uber die Veranderungen physikalischer und chemischer Eigenschaften in Abhangigkeit vom Element und den Substituenten sowie uber die thermische und photochemische Reaktivitat dieser Systeme, wobei zweiwertige Carben-Analoga nachgewiesen wurden. Parallel zu den experimentellen Arbeiten wurden an nahezu allen im Beitrag diskutierten Stammverbindungen Rechnungen durchgefuhrt. Einige Polycyclen weisen den Weg zu Verbindungen mit einer Element-Element-Dreifachbindung.

Verbindungen mit SiSi-, GeGe- und SnSn-Doppelbindungen sowie gespannte Ringsysteme mit Si-, Ge- und Sn-Gerüsten

Dehydrogenative coupling of hydrostannanes catalyzed by transition-metal complexes.

Fourier transform NMR spectroscopy of organotin compounds

Preparation and characterisation of branched decaorganyltetratins, a new class of organotin compound

A comparison of Mossbauer isomer shifts and direct Sn, Sn-coupling constants for a series of di- and polytin compounds indicates that the s-electron density at the Sn-atom has little influence on this coupling.

Mostafa El-Behairy

Papers

Fourier transform NMR spectroscopy of organotin compounds

Preparation and characterisation of branched decaorganyltetratins, a new class of organotin compound

On the Relation between One‐Bond Coupling Constants and the s‐Electron Density at the Nucleus

On the relation between one-bond coupling constants and the s-electron density at the nucleus